1. Field of the Invention
The invention relates to an X-ray detector, comprising a gas-filled ionization space which is closed by a radiation entrance window which is covered with an electrically conductive material. The invention also relates to an X-ray analysis apparatus comprising such a detector.
2. Description of the Related Art
In known X-ray detectors of this type, notably on the inner side of the radiation entrance window there is provided an electrically conductive layer for draining electric charges during measurement. Such a layer notably consists of aluminum, because this material can be comparatively easily provided by vapor deposition, has a comparatively high electrical conductivity and notably also because aluminum, having a low atomic number, combines low density with a mass absorption value such that it has a comparatively low specific absorption also for soft X-rays.
During analysis of elements having a low atomic number, such as borium and beryllium, however, the absorption of the aluminum layer is still found to be disturbing. This is due notably to the fact that the aluminum layer cannot be very thin because of the required adequate electrical conductivity and stability.